The present invention relates to support rings for vehicle tires, which are mounted inside the tires on the wheel rim in order to take up the vehicle load in the event of reduced tire pressure. In particular, the support ring has a particular groove pattern on the outer surface for the purpose of distributing any lubricating fluids and for dissipating any heat build-up.
Tires are primarily supported by internal air pressure. A number of tire designs now exist that use a support ring located inside the tire to support the tire when the tire is operated in an underinflated condition. The use of a support ring of annular shape made of a flexible elastomeric material has been known for a long time. To improve the endurance performance of the support, a lubricant is generally included inside the tire cavity in order to lubricate any contact there may be between the outer surface of the ring and the inside of the tire.
One such support ring is disclosed in U.S. Pat. No. 5,891,279. The ring has a set of longitudinal grooves formed on the outer surface of the ring. Any lubricant in the tire cavity wilt remain in the grooves during rotation of the tire, and does not have the means to travel across the ring surface.
Other rings have employed the use of holes extending completely through the support ring. Such designs might be good for heat dissipation, but are not satisfactory for keeping lubricant on the outermost surface of the ring.
The present invention is aimed at meeting the goals of allowing the lubricant to travel across the surface of the ring and having sufficient grooving for good heat dissipation.
Disclosed is a support ring intended to be mounted on a wheel rim inside a tire equipping a vehicle, in order to support the tread strip of the tire in the event of an underinflated condition of the tire. The support has a base intended to fit around the wheel rim, a cap, and an annular body connecting the base and the cap. In accordance with the invention, the cap has at least one circumferential groove and a plurality of lateral grooves resulting in a net-to-gross ratio in the range of 75 to 90%.
In one aspect of the disclosed invention, the cap has a centrally located circumferential groove, the groove having sloping rounded walls and a width of 15 to 35% of the width of the cap.
In another aspect of the invention, the lateral grooves decrease in depth as the grooves approach the lateral edge of the cap.
In another aspect of the invention, some of the plurality of lateral grooves extend to the edge of the cap and some of the plurality of lateral grooves do not extend to the edge of the cap.
In another aspect of the invention, the cap has a centrally located circumferential groove dividing the cap into two cap halves. The lateral grooves are located in each cap half. Some of the lateral grooves may extend to the edge of the cap while some of the plurality of lateral grooves do not extend to the edge of the cap. Additionally, the lateral grooves may be curved and the grooves in each cap half may be curved in the same or opposing directions.
In another aspect of the invention, the cap may have further circumferential grooves on each side of the centrally located circumferential groove.